IPTV services are wideband value-added services which provide an interactive TV experience and multimedia service for users by connecting a set top box (STB) to a wideband network and using a computer or a TV set as a display terminal. An IPTV system can provide Video on Demand (VOD), Live TV, Time-shifted TV (TSTV) and TV on Demand (TVOD). The IPTV system is a multi-node architecture. In order to equalize concurrent streams generated when users watch TV, logical nodes are set to manage conceptually areas and are responsible for services in the areas, and master and backup agent servers, magnetic arrays, several blades able to provide service functions are configured under the nodes. Pathways are established in a central node in the IPTV system, and are then relayed to other edge nodes.
Live TV, also called as live service, is one of the basic service forms for IPTV services. Live TV is realized based on live channels. For users, like conventional channel TV, channel switch and channel selection, the live TV is realized in the form of screen menu, which enriches television channels watched by the users. For operators, the live TV is an efficient means for attracting conventional TV users, and its operation key lies in channel features. From the perspective of technical realization, the live TV generally transmits TV program information over IP networks using the Internet Protocol (IP) multicast technique.
TSTV is in a media playing mode in which users can be liberated from conventional program schedules such that the users can perform operations such as pause and backward of live TV programs while watching the programs and fast forward to the moment when the current live TV is played, which subverts the original way of watching TV and brings viewers completely new television experience.
TVOD, which is an extension of the TSTV, makes a segment of program on the live channel into a recorded program for displaying in an electronic program list such that users can demand missed wonderful programs ad libitum and choose programs a few days ago. Thus the IPTV becomes real “my TV”, gets rid of constraint of time, and complies with faster and faster life rhythm of modern people.
The success rate of recording a program (for example, TVOD) is currently high, but failure also exists. For carrier-class operation requirements, failure of recording a program is unacceptable except the problem of channel itself or improper production of the recorded program itself. Excluding serious faults, such as power down, manually stopping of a server of an IPTV system or streaming media blade services, or no signal on a channel, in normal operation of the IPTV system, programs are required to be ensure recorded successfully as much as possible in the following conditions without affecting services: switching between master and backup servers in a short time or network failure in a short time occurs in some of nodes due to too high drop out code rate of the channel.